shaz2010 Posted January 12, 2020 Share Posted January 12, 2020 Hi lads looking at doing some work to the supra and so did a compression test today to check it’s health. So at the minute I’m pretty sure the vss are fooked and the turbo seals to after driving it in the summer last year. So here are the results, I’ve had her running at bpu for about 2-3 years now at 1.4 bar not all the time mostly 1.2bar. Ah and she has about 160k on the clock still pulls like a train apart from the odd puff of smoke on idle at traffic lights after a good push. And a little on start up in the mornings. Warmed the car for about 25 mins to running temp, took the 2 30 amp fuses out. One spark plug at a time starting from front to back and these were the readings From front to back 1 151 2 156 3 156 4 154 5 153 6 152 Also this was throttle body fully open. Does it matter that I left the other spark plugs in as I read this was the way and now I’ve seen you should take all 6 out ?? Thanks lads Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted January 12, 2020 Share Posted January 12, 2020 Hi lads looking at doing some work to the supra and so did a compression test today to check it’s health. So at the minute I’m pretty sure the vss are fooked and the turbo seals to after driving it in the summer last year. So here are the results, I’ve had her running at bpu for about 2-3 years now at 1.4 bar not all the time mostly 1.2bar. Ah and she has about 160k on the clock still pulls like a train apart from the odd puff of smoke on idle at traffic lights after a good push. And a little on start up in the mornings. Warmed the car for about 25 mins to running temp, took the 2 30 amp fuses out. One spark plug at a time starting from front to back and these were the readings From front to back 1 151 2 156 3 156 4 154 5 153 6 152 Also this was throttle body fully open. Does it matter that I left the other spark plugs in as I read this was the way and now I’ve seen you should take all 6 out ?? Thanks lads You need to have all the spark plugs removed in order to remove any resistance from the cylinders as pistons move up and down whilst cranking. Usually a good idea to have a battery charger connected in case your battery is a bit poo and loses some omph by the time you reach cylinder 6. Your results look fairly consistent, but could be skewed by leaving plugs in, may be worth rechecking. If the numbers are accurate then you are slight down on compression compared to a healthy motor, but still have some way to go until you are at ~127psi which is the repair manuals limit for compression. You also seem to be within the 14psi range of highest/lowest cylinder so might be ok. If you are getting smoke on start up and have done 160k then chances are your engine is on the tired end of things. Might be worth getting a garage to give the engine a leak down test, as this can be a better representation of engine sealing health versus a compression test which is a bit of a crude ballpark figure. If you don't do a leakdown then may also be worth doing a wet compression test (drop a teaspoon of oil down into cylinder before testing). If your compression number remains unchanged then likely you are leaking compression via valves. If your compression number shoots up beyond 10psi then likely your rings are a bit worn. Quote Link to comment Share on other sites More sharing options...
shaz2010 Posted January 12, 2020 Author Share Posted January 12, 2020 Cheers mike, ah ok I’ll do it again with all plugs out. The battery was fully charged and I did have a charger just in case. I read that standard factory compression was 156psi? And the higher the results the more carbon the engine would have? She’s going in for some work as in vss and turbo seals (rebuild) if needed. And some other bits to freshen her up. I’ll do another test tomorrow with all plugs out see if that changes anything. Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted January 12, 2020 Share Posted January 12, 2020 Cheers mike, ah ok I’ll do it again with all plugs out. The battery was fully charged and I did have a charger just in case. I read that standard factory compression was 156psi? And the higher the results the more carbon the engine would have? She’s going in for some work as in vss and turbo seals (rebuild) if needed. And some other bits to freshen her up. I’ll do another test tomorrow with all plugs out see if that changes anything. Factory manual specifies 156psi as the lower limit of what it deems healthy. From experience freshly built stock spec 2J's or well looked after ones are in the 165-180 region. Excessive carbon build up normally pushes them into the 190 region. But every engine is different so hard to generalise. Doing a compression test every now and then and tracking results is more useful then taking numbers off the internet. If it were me I'd be doing a combo of dry & wet compression test and a leak down test. That will highlight your engines health far better than just a compression test. Tracking oil consumption vs miles done can also shed some light on how things are with the motor. Quote Link to comment Share on other sites More sharing options...
Mo Reviews Posted January 12, 2020 Share Posted January 12, 2020 My last compression test results were pretty high but upon further examination, there were no signs of any issues. Results below: 1 190 psi 2 190 psi 3 195 psi 4 195 psi 5 190 psi 6 192 psi Quote Link to comment Share on other sites More sharing options...
Jellybean Posted January 13, 2020 Share Posted January 13, 2020 Workshop manual gives you a step by step guide on how to do a compression test and expected results http://www.mkivsupra.net/vbb/content.php?65-Engine-Mechanical-(2JZ-GE) Quote Link to comment Share on other sites More sharing options...
shaz2010 Posted January 13, 2020 Author Share Posted January 13, 2020 Factory manual specifies 156psi as the lower limit of what it deems healthy. From experience freshly built stock spec 2J's or well looked after ones are in the 165-180 region. Excessive carbon build up normally pushes them into the 190 region. But every engine is different so hard to generalise. Doing a compression test every now and then and tracking results is more useful then taking numbers off the internet. If it were me I'd be doing a combo of dry & wet compression test and a leak down test. That will highlight your engines health far better than just a compression test. Tracking oil consumption vs miles done can also shed some light on how things are with the motor. Sound thanks for clearing that up about the figures, I’ll see what the figures are tonight after doing it again. - - - Updated - - - Workshop manual gives you a step by step guide on how to do a compression test and expected results http://www.mkivsupra.net/vbb/content.php?65-Engine-Mechanical-(2JZ-GE) Nice one mate thanks Quote Link to comment Share on other sites More sharing options...
Mo Reviews Posted January 13, 2020 Share Posted January 13, 2020 So according to the manual, 192 psi or more is the compression from factory, but anything above 156 psi with a variance of 14 psi or less, is still acceptable? Quote Link to comment Share on other sites More sharing options...
Style Posted January 13, 2020 Share Posted January 13, 2020 Bare in mind, the figures in the manual are for the higher compression GE engine. So the GTE optimal is a little lower than that. 190's across a GTE sounds a bit high to me but I may be wrong. Or has Mike has pointed out, carbon deposits may drive the numbers up a little. Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted January 13, 2020 Share Posted January 13, 2020 Bare in mind, the figures in the manual are for the higher compression GE engine. So the GTE optimal is a little lower than that. 190's across a GTE sounds a bit high to me but I may be wrong. Or has Mike has pointed out, carbon deposits may drive the numbers up a little. Annoying that the manual dosen't make a distinction between GE & GTE compression figures. I tend to see around the 200-215 psi range on GE's still running 10:1 compression. Quote Link to comment Share on other sites More sharing options...
shaz2010 Posted January 13, 2020 Author Share Posted January 13, 2020 (edited) So Is say 165psi the “perfect” compression for a TT? And I’m compression terms is 10psi loss a lot? To be fair my car has never missed a beat since owning her. It gets serviced by myself and change oil filter fuel filter coolant diff oil etc etc more than required so has been looked after. Just turbo and vvs are nackad. I’m hoping the block is still strong but a rebuild would make all that a lot better. Edited January 13, 2020 by shaz2010 (see edit history) Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.